Corrosion on pipe connections.

[r.bartlett]

Perhaps I'm missing something but isn't this just melted insulation sticking to the pipework

no that's rust and rot.. compare the two top and bottom.. especially where the threaded section on the tank is.. that's where the leak is..

 

[gpbeck]

What’s the sodium content of the water?

 

[Chuck]

The first image seems to show a trail of corrosion running vertically down the white tank. Could it be a leak above the fittings is letting fluid run down and corrode the lower ones?

 

[r.bartlett]

What’s the sodium content of the water?

I have no idea but it's rotting from the outside in so it's not whatever is in the tank/pipes it's something else. the bottom connection is undamaged..

 

[r.bartlett]

The first image seems to show a trail of corrosion running vertically down the white tank. Could it be a leak above the fittings is letting fluid run down and corrode the lower ones?

the trail is from the corroded fitting down to the uncorroded one..

 

[king of pipes]

I would be contacting the manufactures of the solar cylinder for their input is there a sacrificial zinc/Aluminium anode installed ? In the unit ? if this has failed then it could be the cause,?.. kop

 

[Ric2013]

This has already been answered?

Not really. You said they don't tend to use inhibitor so you assumed it's just water. Glycol is a kind of antifreeze that also raises the boiling point so non-use of inhibitor isn't a reason to assume non-use of glycol.